As methods for decorating a surface of a large plastic molded article (referred to as “molded article” hereinafter), methods exist which perform decoration by transferring a thermal transfer foil design to a surface of a molded article by causing a thermal transfer foil to cover a molded article; pressing the perimeter of the thermal transfer foil; attaching the thermal transfer foil to the molded article by means of vacuum extraction, whereupon the foil adopts a shape like that of the molded article; and lowering and raising a heated “molded rubber mold”. This method is known as three-dimensional hot stamping. This technique will be described in detail hereinbelow using specific examples.
First, a molded article such as that illustrated in FIG. 1 is presented as an article for decoration. The dimensions of this molded article are: length 900 mm, width 300 mm, height 50 mm, and wall face height 25 mm. Meanwhile, an outside view and a cross-sectional view of the molded rubber mold for hot stamping are shown in FIGS. 2, 3. A bar-shaped heater 9 is fitted thereon, and [the molded rubber mold with heater] is mounted on a stamp device which has a lowering and raising mechanism as shown in FIG. 4. This stamp device has a slide table 4 on whose inner face a support jig 5, which is for securing a product made of aluminum manufactured so as to match the shape of the molded article (referred to as “support jig” hereinafter), is arranged.
With regard to the mold support jig and device as described above, first the molded article 6 is fixed to the top of the support jig 5 as shown in FIG. 4. Thereupon, a thermal transfer foil 7 is set using a foil chuck over a space into which the slide table is to be introduced once. Next, the slide table is moved to below the molded rubber mold as far as the state in FIG. 5, and the thermal transfer foil 7 is secured by lowering the foil clamp 8. Then, cutting of the thermal transfer foil 7 on the roll side is performed using a foil cutter. Next, by removing the air in an enclosure 10 contained by the support jig 5 and the molded article 6, using a vacuum pump, the thermal transfer foil 7 is caused to adhere to the molded article 6. Following adequate adhesion of the thermal transfer foil 7, heat and pressure are applied by lowering the molded rubber mold 3 as shown in FIG. 6, such that the design is transferred to the molded article 6. Thereafter, after raising the molded rubber mold 3 as shown in FIG. 7, the position of the slide table 4 is moved as shown in FIG. 8, and after peeling the thermal transfer foil 7 from the surface of the molded article 6, the molded article 6 thus decorated is removed. Of course, the peeling of the thermal transfer foil 7 may also be performed following removal of the molded article 6 from the support jig 5. Following peeling of the thermal transfer foil 7, in cases where foil burrs remain on the grating portions, the grating portions are rubbed using a sponge or the like, and then, by running a cleaner, finishing of the decorated article is performed.
In addition, methods in which the thermal transfer foil 7 is supplied continuously using a foil roll, and the thermal transfer foil 7 is peeled in foil peeling bars after transfer have also already been implemented as mass production methods.